1. Technical Field
The present invention relates to a display system for calibrating luminance unevenness, color unevenness, etc. on the display sections thereof. More particularly, the present invention relates to a display system capable of performing calibration while content is displayed, and to a recording medium on which computer programs for causing a computer to perform calibration are recorded.
2. Description of Related Art
In recent years, a multi-display system (or a multi-vision system) constituting a single large display screen is used in which a plurality of display devices, each having a display section formed of an LCD (Liquid Crystal Display) or a plasma display, are arranged. In such a multi-display system, a large display screen is formed of a plurality of display devices. Hence, it is possible to produce various visual effects; for example, a large image is displayed, different images are displayed on the respective display devices, and the same image is displayed on the display devices disposed symmetrically with each other. With these effects, the multi-display system is used for digital signage to obtain great advertising effects. Furthermore, the multi-display system is sometimes used to relay images effectively or to produce events at an open space, such as an event site or a public facility.
In the multi-display system, a continuous image is sometimes displayed on two display devices adjacent to each other, for example, in the case that one image is displayed on the display sections formed of a plurality of display devices. It is therefore necessary to reduce the differences in color and luminance among the respective display sections. On the other hand, the display properties of the display sections, such as color representation and luminance gradation property, have individual differences. Furthermore, color drift or luminance change occurs because the display properties vary due to temperature change or deterioration with age. For this reason, in the multi-display system, it is necessary to periodically perform calibration to reduce the differences in color and luminance among the display sections formed of the plurality of display devices. Hence, a method capable of performing this kind of calibration simply and efficiently is gaining importance as such multi-display systems become widely used.
As an example of a simple calibration method according to a prior art, a method has been proposed in which a color chart serving as a standard is displayed on a display section and is imaged using a digital camera, and the profile of the display section is obtained from the image signal of the captured image. In the prior art, for the purpose of obtaining an image signal represented in a color space independent of a capturing device, that is, an image signal in the color space inherent in the display section to be subjected to calibration, from the image signal of the captured image, the profile of the capturing device (image sensor) is applied to the image signal and converted so as to eliminate the elements of the color space inherent in the image sensor.